SAT Math 2 & Chemistry Help Needed

I just signed up for these 2 (Nov 5th) tests and began to study today. I am cool with math bc i can just practice it and do fine but chem is my issue, i took it a year ago and remember a little bit of it. I am sure that i’ll do fine when i get then\ knowledge back with studying and practice. What should i do to study for it? Any sources available online?